In general, 10H-dibenzo[b,f][1,4]thiazepin-11-one is applied as an intermediate to formulate medicines for treatment of psychiatric disorders, and is typically produced as follows.
That is, 1-chloro-2-nitrobenzene reacts with thiophenol, to prepare 2-nitrodiphenylsulfide, after which a nitro group of the prepared compound is reduced to an amino group. The reduced amino group is activated to isocyan using phosgene, which is then cyclized by use of aluminum trichloride, to give 10H-dibenzo[b,f][1,4]thiazepin-11-one, which is disclosed in Helv. Chim Acta, 48, 336 (1965). However, the above method is disadvantageous in terms of difficulties of commercial production, due to the use of hazardous phosgene for the cyclization.
Also, in the above literature (Helv. Chim Acta, 48, 336 (1965)), there is disclosed the preparation of 10H-dibenzo[b,f][1,4]thiazepin-11-one by reacting 2-chloronitrobenzene with thiosalicylic acid methyl ester. However, this method suffers from the use of expensive thiosalicylic acid methyl ester, thus negating economic benefits. In addition, since all the reactions take place in the organic solvent, the above method is environmentally unfriendly.
Likewise, a method of preparing 10H-dibenzo[b,f][1,4]thiazepin-11-one by activating 2-aminodiphenylsulfide by use of chloroformic acid phenyl ester is disclosed in European Patent Laid-open Publication Nos. 0240228 and 028236. However, the above method is environmentally unfriendly, because excessive amounts of acidic wastewater are generated by using polyphosphoric acid, which is a strong acid, as the solvent for the cyclization. Further, it is difficult to commercially produce the desired product.
Disclosed in J. Med. Chem. 44, 372–389, 2001, a method of preparing 10H-dibenzo[b,f][1,4]thiazepin-11-one starting from 2-bromonitrobenzene and thiosalicyiic acid is difficult to commercially apply, due to the use of hazardous tin chloride upon the reduction of the nitro group.